scholarly journals A significant mutual inclination between the planets within the π Mensae system

2020 ◽  
Vol 640 ◽  
pp. A73 ◽  
Author(s):  
Robert J. De Rosa ◽  
Rebekah Dawson ◽  
Eric L. Nielsen
Keyword(s):  
Orbital Plane ◽  
Credible Interval ◽  
Position Angle ◽  
Outer Planet ◽  
Earth Systems ◽  
System A ◽  
Extrasolar Systems ◽  
Orbital Geometry ◽  
Mutual Inclination ◽  
General Relativistic

Context. Measuring the geometry of multi-planet extrasolar systems can provide insight into their dynamical history and the processes of planetary formation. These types of measurements are challenging for systems that are detected through indirect techniques such as radial velocity and transit, having only been measured for a handful of systems to date. Aims. We aim to place constraints on the orbital geometry of the outer planet in the π Mensae system, a G0V star at a distance of 18.3 pc that is host to a wide-orbit super-Jovian (M sin i = 10.02 ± 0.15MJup) with a 5.7-yr period and an inner transiting super-Earth (M = 4.82 ± 0.85M⊕) with a 6.3-d period. Methods. The reflex motion induced by the outer planet on the π Mensae star causes a significant motion of the photocenter of the system on the sky plane over the course of the 5.7-year orbital period of the planet. We combined astrometric measurements from the HIPPARCOS and Gaia satellites with a precisely determined spectroscopic orbit in an attempt to measure this reflex motion, and in turn we constrained the inclination of the orbital plane of the outer planet. Results. We measure an inclination of ib = 49.9−4.5+5.3 deg for the orbital plane of π Mensae b, leading to a direct measurement of its mass of 13.01−0.95+1.03 MJup. We find a significant mutual inclination between the orbital planes of the two planets, with a 95% credible interval for imut of between 34.°5 and 140.°6 after accounting for the unknown position angle of the orbit of π Mensae c, strongly excluding a co-planar scenario for the two planets within this system. All orbits are stable in the present-day configuration, and secular oscillations of planet c’s eccentricity are quenched by general relativistic precession. Planet c may have undergone high eccentricity tidal migration triggered by Kozai-Lidov cycles, but dynamical histories involving disk migration or in situ formation are not ruled out. Nonetheless, this system provides the first piece of direct evidence that giant planets with large mutual inclinations have a role to play in the origins and evolution of some super-Earth systems.

scholarly journals Discovery and characterization of the exoplanets WASP-148b and c

2020 ◽  
Vol 640 ◽  
pp. A32
Author(s):  
G. Hébrard ◽  
R. F. Díaz ◽  
A. C. M. Correia ◽  
A. Collier Cameron ◽  
J. Laskar ◽  
...  
Keyword(s):  
Orbital Period ◽  
Orbital Plane ◽  
Outer Planet ◽  
Velocity Measurements ◽  
Mean Motion Resonances ◽  
Keplerian Orbits ◽  
Mutual Inclination ◽  
Long Timescales ◽  
True Mass

We present the discovery and characterization of WASP-148, a new extrasolar system that includes at least two giant planets. The host star is a slowly rotating inactive late-G dwarf with a V = 12 magnitude. The planet WASP-148b is a hot Jupiter of 0.72 RJup and 0.29 MJup that transits its host with an orbital period of 8.80 days. We found the planetary candidate with the SuperWASP photometric survey, then characterized it with the SOPHIE spectrograph. Our radial velocity measurements subsequently revealed a second planet in the system, WASP-148c, with an orbital period of 34.5 days and a minimum mass of 0.40 MJup. No transits of this outer planet were detected. The orbits of both planets are eccentric and fall near the 4:1 mean-motion resonances. This configuration is stable on long timescales, but induces dynamical interactions so that the orbits differ slightly from purely Keplerian orbits. In particular, WASP-148b shows transit-timing variations of typically 15 min, making it the first interacting system with transit-timing variations that is detected on ground-based light curves. We establish that the mutual inclination of the orbital plane of the two planets cannot be higher than 35°, and the true mass of WASP-148c is below 0.60 MJup. We present photometric and spectroscopic observations of this system that cover a time span of ten years. We also provide their Keplerian and Newtonian analyses; these analyses should be significantly improved through future TESS observations.

scholarly journals Inclinations of Circumbinary Planets: Assembly of Protoplanetary Discs and Secular Binary-Disc Interaction

2012 ◽  
Vol 8 (S293) ◽  
pp. 146-151
Author(s):  
Dong Lai ◽  
Francois Foucart
Keyword(s):  
Binary Stars ◽  
Outer Region ◽  
Orbital Plane ◽  
Close Binary ◽  
Back Reaction ◽  
Star Forming ◽  
Transiting Planets ◽  
Close Binary Stars ◽  
Mutual Inclination ◽  
Protoplanetary Discs

AbstractThe Kepler satellite has discovered a number of transiting planets around close binary stars. These circumbinary systems have highly aligned planetary and binary orbits. In this paper, we explore how the mutual inclination between the planetary and binary orbits may reflect the physical conditions of the assembly of protoplanetary discs and the interaction between protostellar binaries and circumbinary discs. Given the turbulent nature of star-forming molecular clouds, it is possible that the infalling gas onto the outer region of a circumbinary disc rotates around a different axis compared to the central protostellar binary. Thus, the newly assembled circumbinary disc can be misaligned with respect to the binary. However, the gravitational torque from the binary produces warp and twist in the disc, and the back-reaction torque tends to align the disc and the binary orbital plane. We present a new, analytic calculation of this alignment torque, and show that the binary-disc inclination angle can be reduced appreciably after the binary accretes a few percent of its mass from the disc. Since mass accretion onto the proto-binary is very likely to occur, our calculation suggests that in the absence of other disturbances, circumbinary discs and planets around close (sub-AU) stellar binaries are highly aligned with the binary orbits, while discs and planets around wide binaries can be misaligned.

scholarly journals VLT/SPHERE astrometric confirmation and orbital analysis of the brown dwarf companion HR 2562 B

2018 ◽  
Vol 615 ◽  
pp. A177 ◽  
Author(s):  
A.-L. Maire ◽  
L. Rodet ◽  
C. Lazzoni ◽  
A. Boccaletti ◽  
W. Brandner ◽  
...  
Keyword(s):  
Orbital Motion ◽  
Orbital Plane ◽  
Real Data ◽  
Far Infrared ◽  
Brown Dwarf ◽  
Orbital Parameters ◽  
System A ◽  
Low Mass ◽  
Debris Disk ◽  
Orbital Periods

Context. A low-mass brown dwarf has recently been imaged around HR 2562 (HD 50571), a star hosting a debris disk resolved in the far infrared. Interestingly, the companion location is compatible with an orbit coplanar with the disk and interior to the debris belt. This feature makes the system a valuable laboratory to analyze the formation of substellar companions in a circumstellar disk and potential disk-companion dynamical interactions. Aims. We aim to further characterize the orbital motion of HR 2562 B and its interactions with the host star debris disk. Methods. We performed a monitoring of the system over ~10 months in 2016 and 2017 with the VLT/SPHERE exoplanet imager. Results. We confirm that the companion is comoving with the star and detect for the first time an orbital motion at high significance, with a current orbital motion projected in the plane of the sky of 25 mas (~0.85 au) per year. No orbital curvature is seen in the measurements. An orbital fit of the SPHERE and literature astrometry of the companion without priors on the orbital plane clearly indicates that its orbit is (quasi-)coplanar with the disk. To further constrain the other orbital parameters, we used empirical laws for a companion chaotic zone validated by N-body simulations to test the orbital solutions that are compatible with the estimated disk cavity size. Non-zero eccentricities (>0.15) are allowed for orbital periods shorter than 100 yr, while only moderate eccentricities up to ~0.3 for orbital periods longer than 200 yr are compatible with the disk observations. A comparison of synthetic Herschel images to the real data does not allow us to constrain the upper eccentricity of the companion.

scholarly journals A low-mass stellar companion to the young variable star RZ Psc

2020 ◽  
Vol 496 (1) ◽  
pp. L75-L79
Author(s):  
Grant M Kennedy ◽  
Christian Ginski ◽  
Matthew A Kenworthy ◽  
Myriam Benisty ◽  
Thomas Henning ◽  
...  
Keyword(s):  
Linear Polarization ◽  
Variable Star ◽  
Orbital Motion ◽  
Orbital Plane ◽  
Position Angle ◽  
Circumstellar Dust ◽  
Primary Star ◽  
Infrared Excess ◽  
Low Mass ◽  
Rz Psc

ABSTRACT RZ Psc is a young Sun-like star with a bright and warm infrared excess that is occasionally dimmed significantly by circumstellar dust structures. Optical depth arguments suggest that the dimming events do not probe a typical sightline through the circumstellar dust, and are instead caused by structures that appear above an optically thick mid-plane. This system may therefore be similar to systems where an outer disc is shadowed by material closer to the star. Here, we report the discovery that RZ Psc hosts a $0.12\, \mathrm{ M}_\odot$ companion at a projected separation of 23 au. We conclude that the disc must orbit the primary star. While we do not detect orbital motion, comparison of the angle of linear polarization of the primary with the companion’s on-sky position angle provides circumstantial evidence that the companion and disc may not share the same orbital plane. Whether the companion severely disrupts the disc, truncates it, or has little effect at all will require further observations of both the companion and disc.

scholarly journals Influence of the inclination damping on the formation of planetary systems

2014 ◽  
Vol 9 (S310) ◽  
pp. 220-222
Author(s):  
Sotiris Sotiriadis ◽  
Anne-Sophie Libert ◽  
Kleomenis Tsiganis
Keyword(s):  
Planetary Systems ◽  
Type Ii ◽  
Spin Orbit ◽  
Resonant Interactions ◽  
Extrasolar Systems ◽  
Mass Ratios ◽  
Mutual Inclination ◽  
Multiple Resonances ◽  
Hydrodynamical Simulations

AbstractHighly non-coplanar extrasolar systems (e.g. Upsilon Andromedae) and unexpected spin-orbit misalignment of some exoplanets have been discovered. In Libert and Tsiganis (2011), a significant increase of the mutual inclination of some multi-planet systems has been observed during the type II migration, as a result of planet-planet scattering and/or resonant interactions between the planets. Here we investigate the effect of the inclination damping due to planet-disk interactions on the previous results, for a variety of planetary systems with different initial configurations and mass ratios. Using the damping formulae for eccentricity and inclination provided by the numerical hydrodynamical simulations of Bitschet al.(2013), we examine their impact on the possible multiple resonances between the planets and how the growth in eccentricity and inclination is affected.

scholarly journals Evidence for a high mutual inclination between the cold Jupiter and transiting super Earth orbiting π Men

2020 ◽  
Vol 497 (2) ◽  
pp. 2096-2118 ◽  
Author(s):  
Jerry W Xuan ◽  
Mark C Wyatt
Keyword(s):  
Radial Velocity ◽  
Giant Planets ◽  
Spin Axis ◽  
Spin Orientation ◽  
Outer Planets ◽  
Mutual Inclination ◽  
General Relativistic ◽  
Invariable Plane ◽  
Gaia Dr2 ◽  
Protoplanetary Discs

ABSTRACT π Men hosts a transiting super Earth (P ≈ 6.27 d, m ≈ 4.82 M⊕, R ≈ 2.04 R⊕) discovered by TESS and a cold Jupiter (P ≈ 2093 d, msin I ≈ 10.02 MJup, e ≈ 0.64) discovered from radial velocity. We use Gaia DR2 and Hipparcos astrometry to derive the star’s velocity caused by the orbiting planets and constrain the cold Jupiter’s sky-projected inclination (Ib = 41°−65°). From this, we derive the mutual inclination (ΔI) between the two planets, and find that 49° < ΔI < 131° (1σ) and 28° < ΔI < 152° (2σ). We examine the dynamics of the system using N-body simulations, and find that potentially large oscillations in the super Earth’s eccentricity and inclination are suppressed by general relativistic precession. However, nodal precession of the inner orbit around the invariable plane causes the super Earth to only transit between 7 and 22 per cent of the time, and to usually be observed as misaligned with the stellar spin axis. We repeat our analysis for HAT-P-11, finding a large ΔI between its close-in Neptune and cold Jupiter and similar dynamics. π Men and HAT-P-11 are prime examples of systems where dynamically hot outer planets excite their inner planets, with the effects of increasing planet eccentricities, planet–star misalignments, and potentially reducing the transit multiplicity. Formation of such systems likely involves scattering between multiple giant planets or misaligned protoplanetary discs. Future imaging of the faint debris disc in π Men and precise constraints on its stellar spin orientation would provide strong tests for these formation scenarios.

scholarly journals A comment on ‘Lense–Thirring frame dragging induced by a fast-rotating white dwarf in a binary pulsar system’ by V. Venkatraman Krishnan et al.

2020 ◽  
Vol 495 (3) ◽  
pp. 2777-2785 ◽  
Author(s):  
Lorenzo Iorio
Keyword(s):  
Parameter Space ◽  
White Dwarf ◽  
Orbital Plane ◽  
Rate Of Change ◽  
Quadrupole Mass ◽  
Frame Dragging ◽  
Mass Moment ◽  
General Relativistic ◽  
Analytical Expressions ◽  
Fast Rotating

ABSTRACT We comment on a recent study reporting evidence for the general relativistic Lense–Thirring secular precession of the inclination I of the orbital plane to the plane of the sky of the tight binary system PSR J1141-6545 made of a white dwarf and an emitting radiopulsar of comparable masses. The quadrupole mass moment $Q_2^\mathrm{c}$ and the angular momentum ${\boldsymbol{S}}^\mathrm{c}$ of the white dwarf cause the detectable effects on I with respect to the present-day accuracy in the pulsar’s timing. The history-dependent and model-dependent assumptions to be made on $Q_2^\mathrm{c}$ and ${\boldsymbol{S}}^\mathrm{c}$, required even just to calculate the analytical expressions for the resulting post-Keplerian precessions, may be deemed as too wide in order to claim a successful test of the Einsteinian gravitomagnetic effect. Moreover, depending on how $Q_2^\mathrm{c}$ is calculated, the competing quadrupole-induced rate of change, which is a major source of systematic uncertainty, may be up to ${\lesssim}30{-}50{{\ \rm per\ cent}}$ of the Lense–Thirring effect for most of the allowed values in the 3D parameter space spanned by the white dwarf’s spin period Ps, and the polar angles $i_\mathrm{c},\, \zeta _\mathrm{c}$ of its spin axis. The possible use of the longitude of periastron ϖ is investigated as well. It turns out that a measurement of its secular precession, caused, among other things, also by $Q_2^\mathrm{c},\, {\boldsymbol{S}}^\mathrm{c}$, could help in further restricting the permitted regions in the white dwarf’s parameter space.

scholarly journals Induced Kozai Migration and Formation of Close-in Planets in Binaries

2008 ◽  
Vol 4 (S253) ◽  
pp. 181-187
Author(s):  
Genya Takeda ◽  
Ryosuke Kita ◽  
Frederic A. Rasio
Keyword(s):  
Inclination Angle ◽  
Extrasolar Planets ◽  
Planetary Systems ◽  
Outer Planet ◽  
Momentum Exchange ◽  
Multiple Star ◽  
Tidal Friction ◽  
Orbital Decay ◽  
Planetary Orbits ◽  
Mutual Inclination

AbstractMany recent observational studies have concluded that planetary systems commonly exist in multiple-star systems. At least ~20%, and presumably a larger fraction, of the known extrasolar planetary systems are associated with one or more stellar companions. These stellar companions normally exist at large distances from the planetary systems (typical projected binary separations are 102–104AU) and are often faint (ranging from F to T spectral types). Yet, secular cyclic angular momentum exchange with these distant stellar companions can significantly alter the orbital configuration of the planets around the primaries. One of the most interesting and fairly common outcomes seen in numerical simulations is the opening of a large mutual inclination angle between the planetary orbits, forced by differential nodal precessions caused by the binary companion. The growth of the mutual inclination angle between planetary orbits induces additional large-amplitude eccentricity oscillations of the inner planet due to the quadrupole gravitational perturbation by the outer planet. This eccentricity oscillation may eventually result in the orbital decay of the inner planet through tidal friction, as previously proposed as Kozai migration or Kozai cycles with tidal friction (KCTF). This orbital decay mechanism induced by the binary perturbation and subsequent tidal dissipation may stand as an alternative formation channel for close-in extrasolar planets.

scholarly journals Proper stellar directions and astronomical aberration

2009 ◽  
Vol 5 (S261) ◽  
pp. 130-134
Author(s):  
Mariateresa Crosta ◽  
Alberto Vecchiato
Keyword(s):  
General Relativity ◽  
Proper Motion ◽  
Measurement Accuracy ◽  
Appropriate Use ◽  
System A ◽  
Correct Definition ◽  
Physical Task ◽  
General Relativistic ◽  
Relativistic Models ◽  
Definition Of

AbstractThe general relativistic definition of astrometric measurement needs an appropriate use of the concept of reference frame, which should then be linked to the conventions of the IAU Resolutions (Soffel et al., 2003), which fix the celestial coordinate system. A consistent definition of the astrometric observables in the context of General Relativity is also essential to find uniquely the stellar coordinates and proper motion, this being the main physical task of the inverse ray tracing problem. Aim of this work is to set the level of reciprocal consistency of two relativistic models, GREM and RAMOD (Gaia, ESA mission), in order to guarantee a physically correct definition of light direction to a star, an essential item for deducing the star coordinates and proper motion within the same level of measurement accuracy.

scholarly journals Mutual inclinations between giant planets and their debris discs in HD 113337 and HD 38529

2020 ◽  
Vol 499 (4) ◽  
pp. 5059-5074
Author(s):  
Jerry W Xuan ◽  
Grant M Kennedy ◽  
Mark C Wyatt ◽  
Ben Yelverton
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Giant Planets ◽  
Outer Planet ◽  
Small Probability ◽  
Outer Planets ◽  
Planetary Orbits ◽  
Disc Material ◽  
Mutual Inclination ◽  
Gaia Dr2

ABSTRACT HD 113337 and HD 38529 host pairs of giant planets, a debris disc, and wide M-type stellar companions. We measure the disc orientation with resolved images from Herschel and constrain the three-dimensional orbits of the outer planets with Gaia DR2 and Hipparcos astrometry. Resolved disc modelling leaves degeneracy in the disc orientation, so we derive four separate planet–disc mutual inclination (ΔI) solutions. The most aligned solutions give ΔI = 17°–32° for HD 113337 and ΔI = 21°–45○ for HD 38529 (both 1σ). In both systems, there is a small probability (<0.3 per cent) that the planet and disc are nearly aligned (ΔI < 3○). The stellar and planetary companions cause the orbits of disc material to precess about a plane defined by the forced inclination. We determine this as well as the precession time-scale to interpret the mutual inclination results. We find that the debris discs in both systems could be warped via joint influences of the outer planet and stellar companion, potentially explaining the observed misalignments. However, this requires HD 113337 to be old (0.8–1.7 Gyr), whereas if young (14–21 Myr), the observed misalignment in HD 113337 could be inherited from the protoplanetary disc phase. For both systems, the inclination of the stellar spin axis is consistent with the disc and outer planet inclinations, which instead supports system-wide alignment or near alignment. High-resolution observations of the discs and improved constraints on the planetary orbits would provide firmer conclusions about the (mis)alignment status.

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